Discussion

A car covers 240 km at 60 km/hr and returns over the same route at 40 km/hr. What is its average speed for the whole journey ?

Answer: A

Correct answer: 48 km/hr

Average speed is total distance divided by total time, not the mean of the two speeds.

\[\text{Time} = \frac{240}{60} + \frac{240}{40} = 4 + 6 = 10 \text{ hours}\]

\[\text{Average speed} = \frac{480}{10} = 48 \text{ km/hr}\]

It falls below 50 because more of the journey’s time is spent at the slower speed.

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